The present invention relates generally to sterile products and to methods for sterilizing and assembling such products. More particularly, the present invention relates to sterile products and to methods for sterilizing and assembling such products, wherein the products have two or more portions which are mutually incompatible with regard to the method of sterilization.
Pre-sterilized, disposable medical products are commonplace in the United States and other countries throughout the world. One heretofore significant restraint on the design, development, and manufacture of such products has been the fact that certain desirable products would include portions or components which are mutually incompatible from a sterilization standpoint. For example, it may be desirable to provide a unitary, pre-sterilized product which has a sealed liquid or powder drug component and a plastic apparatus component, such as a tubing or flow control set, for dispensing the drug.
The integral product, however, cannot be sterilized after assembly because not all of the components may be subjected to the same form of sterilization. For example, the plastic apparatus component (e.g. the tubing or flow control device) may only be sterilizable with radiation or gas. The drug component, on the other hand, may not be sterilizable with either gas or radiation--gas sterilization would be ineffective to sterilize a sealed drug, while exposing the drug to radiation may lead to product degradation or otherwise have a deleterious effect on the drug.
Accordingly, efforts have been made to devise means for joining, in a sterile manner, components which are individually pre-sterilized. One example of such a product is the blood processing (apheresis) kit manufactured and sold by the Fenwal division of Baxter Healthcare Corporation of Deerfield, Ill. Typically, the blood processing kit (such as those produced by Baxter Healthcare) consists of two or more containers filled with medical solutions, connecting tubes, and a flow control subassembly. The solution containers may be filled with anticoagulant to prevent blood clotting, dextrose as an energy source for blood cells, saline, or other medical liquid utilized in the treatment of the patient or in the collection of blood components. A network of tubing connects the solution containers and the flow control subassembly.
The current process for manufacturing such apheresis kits involves a multi-step process of assembling an entire apheresis kit with empty solution containers; filling separate containers with the desired solution; separately sterilizing the assembled kit (with the empty containers) and the filled containers; transferring in a sterile manner the pre-sterilized solution into the pre-sterilized empty solution containers; and discarding the original (now empty) solution containers.
The sterile transfer of solution is achieved through the use of a sterile docking device such as the device disclosed in U.S. Pat. No. 4,157,723. The sterile docking device shown there utilizes a pair of mating halves, with facing membranes. One half of the docking device is connected to the empty pre-sterilized containers, and the other half is connected to the full pre-sterilized container. After the halves are joined, the docking device is exposed to radiant energy, causing the membranes within the docking devices to melt and form a sterile fluid pathway through the device. Once this pathway is formed, the previously sterilized solution is manually transferred from the original bag to the empty bag attached to the kit. After transfer, the transfer tubing is sealed and cut, and the emptied bags and the docking devices are discarded.
While this process has generally worked satisfactorily, it entails the step of transferring solution from one container to another in a sterile manner and all the extra quality control procedures associated with such a step. Also, once the solution is transferred, the original solution bags and sterile docking devices cannot be reused and must be discarded, adding cost to the final product.
For these reasons, it is a general object of the present invention to provide an improved sterile product of the type described above and improved methods for sterilizing and assembling such products.
This and other objects of the present invention are set forth in the following detailed description of the illustrated embodiment of the present invention.